Download Analysis of Various Thicknesses of Shear Wall with

Analysis of Various Thicknesses of Shear Wall
with Opening and without Opening and their
Percentage Reinforcement
S.H.Jagadale*,
Post Graduate Student
Civil Engineering Department,
Dr.D.Y.Patil School of Engg and Tech,
Charholi(Bk) Pune-412105,India.
[email protected]
N.L. Shelke
Asst. Professor,
Civil Engineering Department,
Dr.D.Y.Patil School of Engg and Tech,
Charholi(Bk) Pune-412105,India.
Abstract: Due to increase in population spacing in India is needed, especially in urban areas.
Structural engineers in the seismic regions across the world often face the pre ssure to de sign
high ri se buildings with stiffne ss irregularities, even though they know the se buildings are
vulnerable under seismic loading. Today’s tall buildings are becoming more and more slender,
leading to the possibility of more sway in comparison with earlier high rise buildings. Improving
the structural system s of tall buildings can control their dynamic re sponse. With more
appropriate structural forms such as shear walls and improved material properties. Lateral
force s of wind and earthquake are usually resisted by shear walls which are parallel to the
direction of lateral load. These shear walls, by their shearing resistance and resi stance to
overturning, transfer the lateral loads to the foundation. In the seismic design of buildings,
reinforced concrete structural walls, or shear walls, act as major earthquake resi sting members.
The properties of the se seismic shear walls dominate the response of the buildings, and
therefore, it is important to evaluate the seismic re sponse of the walls appropriately. A shear
wall may contain many openings due to the functional requirements such as doors and
windows, which may largely affect the overall seismic re sponse of the structure . An earthquake
load is applied to a building of ten stories located in zone V. In this pre sent study, main focus i s
to determine effectiveness of shear wall with various thickne sse s, and al so vertical opening,
staggered opening and without opening has been studied with the help of different models and
also analysi s and observe the behaviour of shear wall with and without openings in shear wall
under seismic loads.
Keywords: Shear Wall, Response spectrum Method, Base, Shear, Time Period.
1.0 INTRODUCTION
1.1. General Information
I
n modern high rise buildings, shear walls are
generally used as a vertical structural element
for resisting the lateral loads that is induced by the
effect of wind and earthquakes, they will have the
strength and stiffness to resist the horizontal
forces. Lateral forces caused by wind, earthquake,
and uneven settlement loads, in addition to the
weight of structure and occupants; create
powerful t wisting (t orsion) forces. These forces
can literally tear (shear) a building apart.
Reinforcing a frame by attaching or placing a rigid
wall inside it maintains the shape of the frame and
* Corresponding Author
prevents rotation at the joints.
Shear walls not only help to prevent
catastrophic collapse, but they also help to
prevent small-scale damage like c racked drywall
and fractured tile. Shear walls play the same role
in houses in high-wind zones. No matter the
source of the force exerted on a house —
atmospheric or tectonic—shear walls are simply
designed to prot ect the home and its occupants.
Finite Element modeling now days is an essential
approach in analyzing and simulating civil
engineering problem numerically.
Shear walls are generally located at the
sides of buildings or arranged in the fo rm of core
that houses stairs and lifts. Shear walls in a
building is a structurally efficient solution to stiffen
the building because they provide t he necessary
lateral strengt h and stiffness to resist horizontal
forces.. They are generally provided alon g bot h
length and width of the building and are locat ed at
the exterior, interior sides of the buildings. Shear
walls are vertical structural elements for resisting
the lateral loads that may be induced by the effect
of wind and earthquakes acting on tall structure.
To reduce the effect of earthquake reinforced
concrete shear walls are used in the building.
These can be used for improving seismic
response of buildings. The provision of shear wall
in building t o achieve rigidity has been found
effective and economical. Shear walls are usually
used in tall building to avoid collapse of buildings.
When shear wall are situated in advantageous
positions, they can form an efficient lateral force
resisting system.
Shear walls may have one or more openings
for functional reasons such as doors, windows,
and other types of openings in shear wall. The
size and location of openings may vary depending
on purpos es of the openings. The size and
location of shear walls is extremely critical.
Properly designed and detailed buildings with
shear walls have shown good performance in past
earthquakes.
effectiveness in minimizing earthquake damage in
structural and nonstructural elements (like glass
windows and building contents).
For this study residential type of structure,
with G+10 building are considered which one of
the frame, with or without opening in shear wall
and also find out their percentage reinforcement
by using finite element software (E TABS) under
earthquake loads.
1.2 Aim & Objectives of Study
Analysis shear wall, wit h or without opening and
staggered opening of various thicknesses.
Objectives of study:1.
To study the Performance of the building with
opening or without opening in shear wall
having varying thickness.
2.
To study the behaviour of vertical opening or
staggered opening in shear wall having
varying thickness.
3.
To study, which thickness of shear walls is
give best result under the action of lateral
loads.
4.
To determine the percentage of reinforcement
in shear wall under the action of lateral loads
in buildings with help of comparison.
Shear walls also provide lateral stiffness to
prevent the roof or floor above from excessive
side-sway. When shear walls are stiff enough,
they will prevent floor and roof framing members
from moving off their supports. Also, buildings that
are s ufficiently stiff will usually suffer less
non-structural damage. When shear walls are
strong enough, then capable of transferring lateral
forces from walls to next element as a path- floors,
roofs to the ground foundation in a direction
parallel to their planes a shear walls, floors,
foundation walls, footings.
Shear walls in high seismic regions require
special detailing. However, in past earthquakes,
even buildings with sufficient amount of walls that
were not specially detailed for seismic
performance (but had enough well distributed
reinforcement) were saved from collapse. Shear
wall buildings are a popular choice in many
earthquake prone countries, like Chile, New
Zealand and USA. Shear walls are easy to
construct, because reinforcement detailing of
walls is relatively straightforward and therefore
easily implemented at site. Shear walls are
efficient, both in terms of construction cost and
Fig.1: Concept of with and without opening in
shear wall
2.0 MODELLING AND ANALYSIS
In this Project, the model was meshed in
order to obtain results with higher accuracy. The
earthquake load and load combinations were
applied as per IS 1893 – 2002 and the seismic
analysis was done by response spectrum method.
In this study, zone given V because in that
area eart hquake occure more time and also their
frequency is more. The results obtained are
compared for the displacement and base shear at
different storey levels
2.1 Location of Shear Wall
When shear
wall
are situated in
advantageous positions, they can form an efficient
lateral force resisting system. They are generally
provided along both length and width of the
building and are located at the exterior, interior
sides of the buildings. Shear wall located as a
symmetrically to reduce effects of twist. Symmetry
can be along one or bot h the direction. Shear
walls in both directions, which is a more realistic
situation because both wind and earthquake
forces need to be resisted in both directions.
Model 3 – Staggered opening in shear wall
structure
300 mm thicknesses:Model 4 – Without opening in shear wall structure
Model 5 – Vertical opening in shear wall structure
Model 6 – Staggered opening in shear wall
structure
Figure 2 and Figure 3 show Grid -Plan of RCC
building and elevation of building respectively.
Some shear wall are used for Lift wall and
they are situated in interior of structure. These
shear walls are not providing a opening.
2.2. Preliminary data required for analysis
Fig.3: Elevational Plan for RCC structure
Fig.2: Grid Plan for RCC layout
2.2.1 Plan of the building model are given
below
2.2.2 Code of Practice
200 mm thicknesses:-
Number of codes are us ed for design and
analysis of RCC structure, but in that study, refer a
following IS codes-
Model 1 – Without opening in shear wall structure
IS 456 - 2000-Plain and Reinforced Concrete.
Model 2 – Vertical opening in shear wall structure
IS 875 Parts-I -Code of Practice for Design Dead
Loads
Shear3 Wall
3
For Buildings and Structures
IS 875 Parts-I I-Code of Practice for Design Live
Loads
4
For Buildings and Structures.
IS 875 Parts-III -Code of Practice for Design Wind
Loads
5
Thickness
200mm, 300mm
4
Size of column
300 mm x 600
5
Size of beam
300mm x 600
6
Depth of slab
150mm
mm
mm
For Buildings and Structures
IS-1893-2002-(Criteria for Earthquake Resistant
Design Of Structures)
6
IS 13920:1993 – Ductile Detailing of Reinforced
Concrete structures
Preliminary data are required foe seismic analysis
are as follows in a tabular form.
1.8m X 2.4m,
Opening
7 of
7
Shear Wall
0.9m X 1.2m
Table 1: Preliminary geometrical data required
for analysis
Sr.No.
Parameter
Typical Floor Plan
1
Dimension
2
Number of Story
Values
22.7m X 18.2
1.2m X 1.2m
Table 3: Preliminary load consideration data
required for analysis
Sr. No.
G+10
1
Parameter
Values
1
Dead Load
As per structure
2
Impoed Load
2KN/m3
Floor height
3
4
Ground Floor
3.5m
Typical Floor
3.0m
Infill wall
150 mm thick
Table 2: Preliminary structural data required
for analysis
Sr. No.
1
Parameter
1
Type of structure
2
Ty pical
3
KN/m3
Special RC
moment
4
4
Water Proofing
Specific5 weight of
5
M25
Reinforcement
Fe 500
Grade
25 KN/m3
concrete
Specific6 weight of
6
Balcony-3KN/m3,
Toilet- 4 KN/m3
resisting frame
Concrete
2
Grade
Floor-1KN/m3,
Terrace Floor- 3
Values
Materials
2
3
Floor Finish
Infill Wall
20 KN/m3
Table 4: Seismic data required for analysis
[As pe IS 1893:2002 (part-I)]
Sr. No
1
2
3
4
5
Parameter
Values
1
Seismic zone
V
2
Zone factor (Z)
0.36
3
Type of soil
Medium
4
Damping
5%
5
Response
5
6
0.8
reduction factor (R)
6
Importance
factor
(I)
lateral forces at all levels above the story under
consideration. The base shear is found to be
much lesser for shear wall with staggered
openings when compared to shear wall with
vertical openings. As the base shear is reduced,
the shear wall with staggered openings will be
less susceptible to damage. However, the base
shear depends upon the existing soil condition at
the site.
1.0 ( For
Residential
Building)
0.7
0.6
0.5
Series 1
0.4
Series 2
0.3
Series 3
Time
Period
0.2
0.1
0
1
3
5
7
9
3.0 OBSERVATION AND RESULT
3.1.1Time Period
Mode
Fig.4: Mode versus Time Period of 200mm thk
shear wall
For seismic analysis, the first mode or the
fundamental time period is the most significant,
which is the inherent property of the building. The
0.9
time period obtained from the analysis for all three
0.8
models is shown in figure. It can be seen that the
staggered openings exhibited a higher value of
0.7
time period when compared to vertical openings,
and without opening in shear wall time period is
0.6
less as compare to with opening in wall, which Time
0.5
indicates that the shear wall with staggered Period
openings can perform better during seismic action
0.4
than the vertical openings and without opening in
0.3
wall.
0.2
These results are comparatively same for
0.1
thickness of 200mm and 300mm s hear wall.
These results are shown as a graphical form
0
Notation:Series 1 = Staggered Opening in shear wall
Series 2 = Vertical Opening in Shear Wall
Series 3 =Without opening in shear wall
3.1.2 Base Shear
Story shear is defined as the sum of design
11
Series 1
Series 2
Series 3
1
3
5
7
9
11
Mode
Fig.5: Mode versus Time Period of 300mm thk
shear wall
Figure shows, without opening in shear wall
base shear is more as compared to with opening
in shear wall in all storey level.
Acknowledgements
6000
5000
4000
Base
Shear
3000
Series 1
2000
Series 2
1000
Series 3
Storey12
Storey10
Storey8
Storey6
Storey4
I would like to thank Principal, Dr. Ashok S.
Kasnale and H.O.D, Dr. Sanjay K. Kulkarni of Civil
Department, who were the source of inspiration
throughout the making of this project stage I and
helped us to accomplish our goals in a much
easier and healthy
Story No.
References
Fig.6: Storey versus Ba se Shear in X Direction
of 200mm thk. Shear Wall
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7000
6000
5000
4000
3000
2000
1000
0
Series 1
Series 2
Series 3
Base
Storey 2
Storey 4
Storey 6
Storey 8
Storey 10
Storey 12
Base
Shear
Storey2
Base
0
I express my profound gratitude to our
project guide Dr. Nagesh L. Shelke for their
inspiring guidance due to which our difficulties and
questions were shaped into the development of
this project and complete support, co-operation
and valuable suggestions.
Story No.
Fig.7: Storey versus Ba se Shear in X Direction
of 200mm thk. Shear Wall
Notations:
Series 1 = Without Opening in shear wall
Series 2 = Vertical Opening in Shear Wall
Series 3 = Staggered opening in shear wall
4.0 CONCLUSION
Performance of staggered opening is a best
in a seismic zone as compared to vertical opening
and without opening in shear wall. Shear base is
less for a staggered opening in shear wall. The
base shear of without opening is more as
compare to opening in shear wall and also
observe that the time period is more with
comparision of vertical opening and without
opening in shear wall
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